Protractor



INVENTOR ATTORN EYS Albert B' v A .is Y

Feb. "24, 1942. A. G. BAUER PRoTRAcToR Filed April 2, 1941 against casual movement from any adjusted posi- Patented Feb. 24, 1942 e yiebriaw Mihf Appiicaionnpriiz, lsilyserial No. 386,540

This invention relates .toi protractors ofthe ypivoted' arm type, and itsllgeneralfobjectis to provide a protractor in which the army is fnormally held xed relative to the protractor body tion,but can be instantly manually -relea'sedfrom its `heldposition to allow free adjustment mere-` ly by applying pressure to they body, and when the pressure is relieved, the arm becomes'iixed, thus it will be seen that my protractor not only eliminates inaccuracies resulting from the arm creeping or becomingaccidentallyf moved, but also the necessity of manipulating `thumb screws or the like now in general use to vholdfthe" arm inadjusted positions. H ff j A further object is to provide a protractor which is reversible or in other words eitherside can be used, and such coupled Iwith-theinstantaneous releasable and automatici-holding feature for the arm, materially expedites the use of theprotractor. i' f f f Another object is to provide a protractor of the character set` forth, that issimple in con'- struction, inexpensive to manufacture, `and ex-j tremelyeflicient in operation, use'and service.V This .invention alsofconsists in certain other features of construction and in the combination and arrangement of the several parts, tobe herein-after fully described,` illustratedin the accompanying drawing and specicallypointed out`in the appended claims. I 1 i -i Y In describing the invention lin detail, refer- -ence will be had to the accompanying/drawing wherein like characters denotef likeforfcorresponding parts throughout the several-views, and 35 in'which: N,

Figure 1 is a view of one side of Ioneform of my protractor, the other side being identical, and

the arm is illustrated in several of-its'fadjusted 4 positions, in fixed and dotted lines.

Figure 2 is an enlarged fragmentarysectional view taken approximately on line `2--`2vof Figure 1, looking in the direction of the arrows. y'

Figure 3 is a sectional view taken" approximately on line 3-3 of Figure 1; looking in the 45 direction of the arrows. f

Figure 4 is a perspective view strip of the form of Figure 1. v l

Figure 5 is a fragmentary side view-of amodiedform. 1 Figure 6 is a sectional view taken e approxi-y mately online 6-6 of Figure 5, -looking'in-the direction of the arrows. y i Referring to the drawing in detailj-and partic-` ularly to the form l`of 1Figures 1 to 4,it 'will 'be 5 of the spring noted that vthe body of myprotractor includes a pair`v of substantially identical plate sections I and v'2, formed from sheet metal or any other material suitable for the purpose, and each secg tion is provided with an elongated4 strip like base 'the inner` or vupper edge may likewise be inclined toward' the lower edge from the arcuatev member to the ear, as shown in Figure 1. Howverf the shape of those edges are not important as far as the invention is concerned, and they may be of any other desirable shape.

l The sections I` and 2 are connected together in spaced parallel relation, with the graduated faces ofthe arcuate members outermost, by a pair of atheaded rivets 6 that have their shanks extending through the base members 3 adjacent to the ends thereof, and while both sections may be loosely mounted on the rivets, at least the section I is loosely mounted to allow free tilting movement thereof toward and away from the section 2 for a purpose which will be `later -apparent; TheA rivet` holes of the base member 3 of the section I are preferably elliptical shape, with their long axes disposed perpendicular to the outer edge of the base member to bring about'the tilting movement set forth.

= Mounted for swinging movement between the sections is a flat arm or blade 1 that is pivoted 0 to and between the ears 5 of the sections, by a hollow vheadless pin 8 fixed in the arm and extendingtherethrough to provide bearings rotatablymounted in the apertures of the ears, as best-shown in Figure 2, and the aperture of the earl of the section I is likewise elliptical in shape to allow for the tilting movement above referred to.4 5 While the entire portion of the arm that is disposed inwardlyv of the inner edge of the arcuate members 4 is reduced as at 9, the wide 50 sides of the arm are further reduced to provide shoulders I0 that are curved to follow the curvature of the outer edges of the members 4 and are disposed in wiping engagement therewith, so that-the latter edges and shoulders cooperate 51 to guide the arm in its movement, as will be apparent upon inspection of Figure 2. 'The corners of the shoulders are preferably cut away in beveled formation and the outer portion of the arm beyond the shoulders is of a Width so that the Wide faces of the arm are flush with or disposed in the same plane with the outer faces of the rivet heads for supporting the protractor in a level position, when in use, as will be apparent.

Disposed between the base members is a relatively thin resilient strip II formed from spring metal or the like and of a length to extend substantially to the ends of the base members, as shown in dotted lines in Figure 1. The strip transversely curved in channel formation for the major portion of its width and throughout its length and the longitudinal edge portions from the inner wall of the channel are substantially iiat and arranged in the same plane` for bearing engagement with the base member of the plate 2, while the outer wall of the channel along its longitudinal center bears against the base member of the section I, as clearly shown in Figure 2. The strip II has holes I2 therein adjacent its inner longitudinal edge, through which extends the shanks of the rivets 6, and a pair of holes I3 are arranged in the strip II at the longitudinal center thereof. Mounted within the holes I3 are teats I4 formed on the base member of the section I by indentations, and the holes I3 provide seats for the teats I4 for rocking movement therein, as will be apparent upon inspection of Figure 2.

From the foregoing, it will be seen that the spring strip II normally urges and holds the arcuate member of the lsection I in bearing engagement with the arm l, so that rboth of the arcuate members cooperate to set up a clamping action against the arm to hold the latter against casual movement relative to the body and in any adjusted position in which it may be set. Such action is brought about due to the. arrangement of the points of connection of the strip II to the rivets 6 and the points of connection of the strip with the lteats, as by such arrangement, the rivets act as fulcrum means for the section I which is normally held in tilted position, with the arcuate member thereof bearingr against the arm. It will be further obvious that when it is desired to release the arm to allow adjustment thereof,

that the base member of the section l is pressed gether for tilting movement of one section totoward the base memberof the section 2, and when the pressure is relieved, the section I will assume its normal clamping position.

In the form of Figures and 6, I provide a strip I5 of rubber or like elastic material that is used in place of the metallic strip II, andV it The remaining structure of the form of Figures 5 and 6 is identical to that of the other form, and the arms of both forms may have numbered linear graduations thereon, if desired, as well as a pointer line cooperating with the indicia graduations, as shown in Figure l.

It is thought from the foregoing description that the advantages and novel features of the invention will be readily apparent.

It is to be understood that changes may be made in the construction and in the combination and arrangement of the several parts, provided that such changes fall within the scope of the appended claims.

What I claim is:

1. A protractor comprising a pair of spaced normally parallel sections, an arm pivotally mounted between the sections for adjustment relativethereto, means connecting the sections together for tilting movement of at least one section toward and away from the arm, and resilient means associated with the sections to bringabout a clamping action thereof against the arm to hold the latter in adjusted positions.

2.,A protractor comprising a pair of spaced normally'parallel body sections, each including a base member, a graduated arcuate member formed on `the base member, an arm pivotally mounted between the base members for adjustment relativeto the arcuate members, means connecting the base members for tilting movement of at least one section toward and away from thearm, and resilient means secured between the base members by the connecting means thereof and bearing against the base members to bring about a clamping action of the arcuate members against the arm to hold the latter in adjusted positions.

3; A protractor comprising a pair of spaced normally parallel body sections formed from sheet material and each including an elongated base member,- a graduated arcuate member having its ends formed on the base member, an ear formed on the base member, an arm extendingbetween-the sections and pivotally connected to the ears for adjustment of the arm relative tothel arcuate members, said arm being shouldered and the shoulders being disposed in wiping engagement with the outer edges of the arcuate members to guide the arm in its movement, means connecting the base members toward andaway from the arm, and a resilient l: strip substantially coextensive with the length of the base members and secured between the latter by the connecting means thereof to norwill be noted that the rivets I6 extend through the strip I5 adjacent the inner longitudinal edge thereof, so that the major portion of the width of the'strip I5 is free from its outer longitudinal edge, to exert an outward pressure against the base member I'I of the plate section I8, for urging and holding the arcuate member i9 thereof against the arm 2D to cooperate with the arcuate member of the plate section 2| to hold the arm 20 in adjusted positions. By that construction, it will be obvious that when pressure is applied to the base member I1, the arm is released to allow adjustment thereof. I provide three rivets I6 in this form, as shown in Figure 5, and the rivet holes of the base member I1 are elliptical shape to allow for the rocking movement of the` plate section I8 relative to its companion plate section.

mally urge the arcuate member of the tiltable section-against the arm for cooperation with the arcuate member of the other section to set up a clamping engagement on the arm to hold the latter inadjusted positions.

4. A protractor comprising a pair of spaced normally parallel body sections formed from sheet material and each including an elongated base member, an arcuate member formed on the base member and having numbered degree graduations onl one face thereof, an ear formed on the base member, an arm extending between the sections and pivotally connected to the ears for adjustment relative to the arcuate members, means connecting the base members together for tilting movement of one section toward and away fro the arm, a resilient strip secured between the base members by the connecting -means thereof and being channeled along its longitudinal center, and the outer face of the wall of the channeled portion bearing against the base member of the tiltable section and the longitudinal edge portions of the strip bearing against the base member of the other section to urge the arcuate member of the tiltable section against the arm to cooperate with the arcuate member of the other section to set up a clamping engagement on the arm to hold the latter in adjusted positions.

5. A protractor comprising a pair of spaced normally parallel body sections, each including an elongated base member, a graduated arcuate member formed on the base member, an ear formed on the base member and extending centrally therefrom, an arm extending between the sections and pivotally connected to the ears for adjustmentof` the arm relative to the arcuate members, rivets connecting the base members together for tilting movement of one section toward and away from the arm, a resilient strip secured between the base members by the rivets and the latter extending through the strip adjacent to the inner longitudinal edge thereof, said strip being channeled along its longitudinal center and having iiat longitudinal edge portions, the outer face of the wall of the chan` neled portion bearing against the base member of the tiltable section and the flat edge portions bearing against the base member of the other section to urge the arcuate member of the tiltable section against the arm to cooperate with the other arcuate member to set up a clamping engagement on the arm to hold the latter in adjusted positions, said strip being provided with holes at the longitudinal center of the channel, and teats on the base member of the tiltable section and mounted in the holes for rockingv movement.

strip adjacent to its inner longitudinal edge for.

the strip to bring about a clamping action of the arcuate members against the arm to hold the latter in adjusted positions.

7. A protractor comprising a pair of spaced normally parallel body sections formed from sheet metal and each including an elongated base member, a graduated arcuate member formed on the base member, an ear formed on the base member, an arm extending between the sections and pivotally connected to the ears for adjustment of the arm relative to the arcuate` members, rivets connecting the base members together for tilting movement of one section toward and away from the arm, a rubber strip substantially coextensive with the length of the base members and secured between the latter by the rivets and said rivets extending through the strip adjacent to the inner longitudinal edge thereof for the portion of the strip outwardly of the rivets to normally urge the arcuate member of the tiltable section against the arm for cooperation with the arcuate member of the other section to set up a clamping engagement on the armto hold the latter in adjusted positions.

ALBERT G. BAUER. 

